Liquid-level gauge



Dec. 27, 1927.

E. RYDER LIQUID LEVEL GAUGE Filed May 28, 1923 J2 (/2572 for" PatentedDec. 27, 1927.

UNITED STATES ELMER RYDER, OF BEBWYN, ILLINOIS.

LIQUID-LEVEL GAUGE.

Application filed lay 28, 1928. Serial No. 641,874.

This invention relates to means for automatically replenishing air tothe air column of a liquid fuel gauge operated by compression of saidcolumn by the liquid in the tank to compensate for air leakage andchanges in said column by expansion and contraction due to heat andcold, so that the gauge may register accurately the amount of liquid inthe tank under such conditions.

The invention has for one of its objects the provision of this means inthe form of a pump device, which may be located in the tank and operatedby the wash of liquid caused by the tilt or jar of the motor vehicle inits travel over a roadway.

Another object of the invention is to provide a device which will notonly be simple in construction and operation, but one that will becompact and [capable of being inserted into and removed from the tankthrough the usual neck provided at the place for the ordinary gasolinegauge of the float kind.

The invention consists further in the matters hereinafter described andmore particularly set forth in the appended claims.

In the accompanying drawings- Fig. 1 is a vertical sectional Viewshowing a device of my invention applied to a liquid fuel tank of anautomobile or other motor vehicle;

Fig. 2 is a vertical sectional view taken on line 2-2 of Fig. 1;

Fig. 3 is an enlarged view showing the cup within and supported on thebottom of the tank and the manner in which the air inlet pipe of mydevice enters the san1e;'and

Fig. 4 is a detail of the check valves.

In the drawings, 1 indicates a liquid fuel tank, such as used on anautomobile. 2 is a pipe extending downward into the tank through the topwall a thereof and having its lower end opening into an inverted cup orlike casing 3 supported above the bottom wall I) of the tank by bracketsor other means 4. The pipe 2 joins a pipe 5, which leads to a gaugedevice 6 on the instrumentboard 7 of the car. This gauge device may takeany desired form, but as shown in Fig. 1 it is in the shape of a U-tubec in which is a column of mercury 8.

The cup or casing 3 fills from below to a level d short of its top wall,as shown. The 'pipes 2 and 5 constitute a conduit from the level d andthe mercury 8 and confine a column of air between such parts.

The upward pressure on this air column by the liquid in the cup 3 variesas the height of the liquid column between it and the level in the tank1 changes. This variation of pressure is registered by the gauge 6, andthus indicates on the board 7 the amount of fuel in the tank 1.

Due to leakage of' air from the conduit 2-5, the level of the liquid inthe cup 3 tends to raise and seek that of the fuel in the tank. Whenthat happens the gauge becomes inoperative. Moreover, heat and coldaffect the accuracy of the gauge in that heat expands the column of airin the conduit, while cold contracts it. When it is remembered that thisconduit in most installations is close to the exhaust pipe, it will beseen that the opportunity afiorded for varying the temperature of theair column is marked. This varies the pressure on this column and makesthe auge 6 register inaccurately the amount of uel in the tank 1.

To overcome these objections, I provide means for automaticallyreplenishing air to said conduit to compensate for changes therein. Thismeans, as shown in the drawings, is in the form of a pump device. Itcomprises a support or bracket 9 extending downward into the tank 1through the neck 10, where the usual float indicator is employed. A cap11 closes the neck 10 and holds the bracket in place. The bracket 9extends toward the bottom of the tank and carries a cylinder 12 closedat its lower end but open at its upper end to receive a plunger orpiston .13. This is loose in the cylinder and is connected by a link 14with a rock arm 15 pivoted to the bracket 9 by a pin 16. Also connectedwith this pin is an arm 17 extending downward toward the bottom of thetank 1 and provided with a wide paddle portion 18, as shown.

Opening into the bottom of the cylinder 12 is a pipe 19, which extendsup along the bracket 9 toward the neck 10 and there by 'a T or otherfitting 20 is connected with a pipe 21 with its upper endin said neck10. The upper end of this pipe 21 opens to the atmosphere to provide anair intake 22 controlled y a spring pressed check valve 23, as shown inFig. 4. Said pipe 21 extends toward the bottom of the tank -1 and hasits lower end entering the inverted cup 3 from below and rising abovethe level d of the fuel therein as shown in dotted lines in Fig. 1 andfull lines in Fig. 3. v In the pipe 21 below the fitting 20 is anotherspri-ng pressed check valve 24, as shown in Fig. 4c.

The device of In invention operates asfollows. The padd e. 18 isarranged transverse to the length of the tank 1 an d thus is in the pathof the wash as the liquid in the tank sur es back and forth due to thetilt or jar 0 a car in passing over a roadway. A swinging movement 15thus imparted to the paddle 18, which through the arm 17 and links 15and 14 reciprocates the plunger 13 up and down in its cylinder 12. Th scylinder 12 being immersed in the liquid in the tank 1 and open at itsupper end allows liquid to fill the space in the cylinder not occupiedby the plunger 13 and also the pipe 19 to the same level as in thetank 1. As the plunger 13 is reciprocated, a surge is created in thepipe 19. The check valve opens on the downward surge and air 1s drawninto the pipe 21 past said-valve. On the upper surge in the pipe 19,this indrawn air is forced past the other check valve 24 and into theconduit 2-5, thus replenishing air in the air column in said conduit.The operationdescribed is repeated as long as the pump is actuated andreplenishing of air to this column automatically effected.

With this resupply of small amounts of 7 air from time to time to theair column, the

amount of air in the same is more or less maintained constant with theresult that the gauge 6 operates substantlally accurate under theconditions heretofore described and thus properly registers the amountof fuel in the tank 1. Moreover, no opportunity is afforded for the airin the air column to be so reduced as to allow the gauge to become inoerative asheretofore.

While l have shown and described in detail herein a device of myinvention as applied to pumping air into the pipe line of a gasolinegauge of the so-called pressure type, it is to be of course understoodthat my device may be utilized in connection with other gauges,particularly the auge shown in my copending application berial No. 578,31 1, filed July 29, 1922, and be made to maintain the level of thefuel at a predetermined dis tance above the level in the tank inaccordance with the invention in that case. Moreover, I do not wish tobe limited to the details of construction and arrangement of parts shownand described, as such may be variously changed and modified withoutdeparting from the spirit and scope of my in-- vention. The pump deviceis made compact to be assed through the neck 10 and may be rea ilyapplied to any standardfuel tank as used on motor cars.

The paddle 18 or arm 17 is made sufficiently heavy to assist in theswinging of the same, which is particularly essential when the tanklevel is low;

I claim as my invention: '1. The combination with a tank for a motorvehicle and to contain a supply of liquid fuel therefor, of a pressureresponsive gauge to be mounted on the vehicle, an inverted cup at thebottom of the tank and open at its lower end to the liquid therein, anair conduit connecting the top of the cup with the gauge, said conduitconfining a column of'air between the gauge and the liquid in the cupfor operating the gauge by the hydrostatic head .of the liquid in thetank acting against said air column for indicating the amount of liquidin the tank, an air pump supported in the tank and having a check valvecontrolled air intake above the maximum level of the liquid in the tank,an air pipe connected with the air intake and opening into the cup abovethe level of the liquid therein for replenishing the supply of air tothe conduit through said cup in the operation of the pump, a paddlepivotally supported in the tank and disposed to be moved back and forthby the wash of the liquid therein, and means connecting the paddle withthe pump for operating the same.

2. The combination with a tank for a motor vehicle and to contain asupply of liquid fuel therefor, of a pressure responsive gauge to bemounted on the vehicle, an air conduit connected with the gauge andextending down intothe liquid in the tank and open to the same, saidconduit serving to confine a column of air between the gauge andtheliquid at the lower end of the con duit for operating the gauge by thehydrostatic head of the liquid in the tank acting against said aircolumn for indicating the amount of liquid in the tank, a fixture having check valve controlled air intake and outlet openings, a pumpsupported in the tank, a pipe connecting the fixture between itsopenings with the pump and containing a column of liquid surged up anddown in the operation of the pump to draw air into said fixture throughits inlet and force air out of the fixture through its outlet, a secondpipe connecting the air outlet of said fixture with said conduit forreplenishing the supply of air thereto in the operation of said pump,and means in the tank and moved by the wash of the liquid therein andconnected with the p1unp for operating the same.

3. The combination with a tank for a motor vehicle and to contain asupply of liquid fuel therefor, of a pressure responsive gauge to bemounted on the vehicle, an inverted cup at the bottom of the tank, anair conduit connecting the gauge with said cup and serving to confine acolumn of air between the two, a cylinder supported in' the tank, aplunger reciprocating in said cylinder through one end and being loosetherein -so that tank liquid may enter the cylinder ahead ofthe'plunger, a fixture having check wash of the li uid therein, andmeans concontrolled air intake and outlet openings, a meeting the pa dlewith the plunger for op- 10 pipe' connect said fixture between itserating t e-same openings with t e end of the cylinder oppo- Intestimony that I claim the foregoing 5 site the Plunger, an air gipeconnecting the as my invention, I .afiix my signature, this outlet 0 thefixturewit the cu a; paddle 19th day of May, 1923. pivotally supportedin the tanfi and disposed to be moved back and forth by the v ELMERRYDER.

